Predicting atmospheric cadmium and lead using honeybees as atmospheric heavy metals pollution indicators. Results of a monitoring survey in Northern Italy

Figures & data

Figure 1. Map of the sampling sites: red circles urban sites, yellow circle suburban sites; blue circles suburban-rural sites.

Table 1. Beehive locations and ARPA monitoring stations considered in the survey.

ID	Beehive location	Sampling site	Heavy metals monitoring station	Distance of the monitoring station from beehive (km)	Cd	Pb
1	Milan Linate, via dello scalo 28	Suburban (Near Linate Airport)	Milan Pascal, Città studi	5.0	X	X
2	Milan Mercato ittico, viale Lombroso	Suburban (Near Highways)	Milan Pascal, Città studi Senato	2.0 2.5	X X	X X
3	Milan Orti di Via Padova, via Esterle	Urban	Milan Pascal, Città studi Milan Senato	1.65 5.0	X X	X X
4	Lodi, via della Baroncina	Metropolitan area (suburban/rural)	Lodi, Via Vignati Sant’Alberto	1.69 1.96	X (not available at the end of the trial)	X (not available at the end of the trial)
5	Magenta, strada Ossona 27		Magenta, Via Turati	1.3	X	X

Table 2. Mean, minimum and maximum values for Cd and Pb on bees in the five sites during the six monitoring months.

	Milan, Linate	Milan, Mercato Ittico	Milan, Orti di Via Padova	Magenta	Lodi
Cd mean, µg g^−1	0.068	0.085	0.141	0.154	0.111
Cd min, µg g^−1	0.026	0.012	0.019	0.028	0.020
Cd max, µg g^−1	0.160	0.247	0.244	0.385	0.266
	Milan, Linate	Milan, Mercato Ittico	Milan, Orti di Via Padova	Magenta	Lodi
Pb mean, µg g^−1	0.213	0.156	0.278	0.238	0.099
Pb min, µg g^−1	0.098	0.088	0.080	0.117	0.039
Pb max, µg g^−1	0.506	0.300	0.741	0.436	0.179

Table 3. Mean Cd and Pb (± SEM) measured on bees in the different sites, over the trial (June–July 2017).

	Cd on bees (mg kg^-1)					Pb on bees (mg kg^-1)
	Milan, Linate	Milan, Mercato Ittico	Milan, Orti di Via Padova	Magenta	Lodi	Milan, Linate	Milan, Mercato Ittico	Milan, Orti di Via Padova	Magenta	Lodi
June	0.042 ± 0.007	0.025 ± 0.009	0.019 ± 0.001	0.030 ± 0.005	0.020 ± 0.003	0.169 ± 0.033	0.088 ± 0.027	0.099 ± 0.004	0.117 ± 0.016	0.071 ± 0.009
July	0.026 ± 0.006	0.163 ± 0.026	0.090 ± 0.014	0.034 ± 0.009	0.043 ± 0.004	0.149 ± 0.068	0.131 ± 0.020	0.093 ± 0.034	0.135 ± 0.009	0.039 ± 0.017
August	0.031 ± 0.001	0.042 ± 0.020	0.056 ± 0.014	0.028 ± 0.004	0.029 ± 0.006	0.098 ± 0.035	0.090 ± 0.046	0.080 ± 0.008	0.151 ± 0.027	0.101 ± 0.014
September	0.036 ± 0.013	0.018 ± 0.004	0.237 ± 0.006	0.166 ± 0.002	0.096 ± 0.003	0.133 ± 0.059	0.145 ± 0.024	0.205 ± 0.025	0.177 ± 0.001	0.093 ± 0.017
October	0.160 ± 0.029	0.012 ± 0.008	0.202 ± 0.015	0.385 ± 0.005	0.212 ± 0.007	0.506 ± 0.214	0.180 ± 0.072	0.741 ± 0.100	0.414 ± 0.020	0.112 ± 0.057
November	0.111 ± 0.033	0.247 ± 0.036	0.244 ± 0.002	0.280 ± 0.024	0.266 ± 0.15	0.220 ± 0.182	0.300 ± 0.002	0.451 ± 0.127	0.436 ± 0.089	0.179 ± 0.027

Table 4. Mean atmospheric concentration of Cd and Pb measured by municipal monitoring units, calculated on the 30 d before bees collection.

	Atmospheric Cd, ng m^-3			Atmospheric Pb, ng m^-3
	Magenta	Milan, Città Studi	Milan, via Senato	Magenta Atmospheric Pb, ng/m3	Milan, Città Studi	Milan, via Senato
June	0.080 ± 0.045	0.060 ± 0.089	0.067 ± 0.045	8.400 ± 5.940	4.900 ± 2.300	5.600 ± 3.185
July	0.133 ± 0.058	0.160 ± 0.055	0.183 ± 0.280	4.200 ± 0.000	8.225 ± 2.738	6.475 ± 4.742
August	0.080 ± 0.045	0.117 ± 0.098	0.173 ± 0.303	2.940 ± 1.150	7.328 ± 5.543	5.534 ± 4.680
September	0.200 ± 0.163	0.300 ± 0.283	0.209 ± 0.089	9.450 ± 4.999	13.148 ± 8.302	9.879 ± 12.299
October	0.280 ± 0.179	0.320 ± 0.110	0.276 ± 0.089	14.500 ± 7.850	24.972 ± 28.600	21.510 ± 17.051
November	0.267 ± 0.115	0.520 ± 0.179	0.285 ± 0.163	11.200 ± 5.285	40.834 ± 39.746	25.851 ± 9.073

Figure 2. Concentrations of atmospheric Cd and its content on bees located in the city of Milan (Orti di via Padova) (the beehive is 1.65 km far from the monitoring station of Milan,Città Studi and 5 km from the monitoring station of Milan, Senato).

Figure 3. Concentrations of atmospheric Pb and its content on bees located in the city of Milan (Orti di via Padova, the beehive is 1.65 km far from the monitoring station of Milan, Città Studi and 5 km from the monitoring station of Milan, Senato).

Data availability statements

The data that support the findings of this study are available on request from the corresponding author, AC.